1、1中文翻译转基因食品的安全问题在引进现代植物育种生物技术和粮食生产系统重组 DNA 技术的早期阶段，努力开始转向对来自于转基因生物体（GMOs）的安全问题，这有关定义国际的和谐评估战略。1988 年，首次在植物上（烟草）成功实验后的两年，国际食品生物技术局（IFBC）公布了对这些新品种安全性评估问题的首份报告（IFBC，1990 年） 。在本报告所述的比较研究的方法，为以后的安全性评价战略奠定了基础。其他组织，如经济合作与发展组织（OECD） ，联合国粮食，农业组织（FAO）世界卫生组织（WHO）和国际生命科学学会（ILSI）组织，都已经为安全评估制定了进一步的指导方针，获得食品安全评估专家的
2、广泛国际共识。在 1993 年，经济合作与发展组织制定的等价概念作为重大指导工具来评估转基因食品，这在随后的几年中得到了进一步的阐述（OECD，1993;经合组织，1996 年，经合组织，1998 年;图 1） 。实质等同的概念是食品安全评估框架的一部分，这个评估框架是依据现存事物充当一个基础来与其对应的转基因产品作对照。现有的食品供应被认为是安全的，因为经历了很长的使用历史，尽管它是公认可能含有多种抗营养物质和有毒物质的食品，在一定的消耗量下，可能会对人类和动物产生有害的影响。应用的概念本身并不是一个安全评估，但有助于确定现有的食品和新产品之间的相似有不同，并作进一步的毒理学来调查。设想三种
3、情景中的转基因植物或食物：（i）等价物;（ii）除了插入特征的等价物;（iii）没有等价物。成分分析的关键部件，包括主要营养成分和天然毒物，是实质等同评估的基础，除了转基因植物的性状和农业特征。在第一种情况下，没有对产品做进一步特定测试的要求，因为该产品已具有与其对应传统产品的特征，他们的消费被认为是安全的，例如，马铃薯淀粉的特点。在第二种情况下，除了插入的特性，该等价物将合适，所以安全检测的重点是这个插入的特征，例如，具有杀虫蛋白的转基因番茄。安全测试，包括具体的毒性测试，这个测试根据新表达蛋白的性质和功能进行，有可能发生意想不到的效果，转基因食品的基因可能转移到人类/动物肠道菌群中;这是新
4、插入性状的潜在变性原理和在饮食上中新食物的作用。在第三种情况下，新作物或食品将不会很大程度上与一个传统等价物对应，并根据新产品的特点，开展了一个新食品的个例评估。 自 1990 年以来，粮农组织（粮食和农业组织的简称）和 WHO（世界卫生组织）已经为现代转基因生物的安全建立讲习班和磋商。在 1996 年，联合粮农组2织/世卫组织（粮农组织/世卫组织，1996 年）提供咨询。有人建议，安全性评2价应基于等价物的概念，这是一个动态的，分析和现有食物相关的新食物的安全。应考虑以下参数，以确定实质等同的转基因植物，分子特征，表型特征，主要营养，毒物和过敏原。 三个水平等价物（完全，部分，没有）与其相对
5、应新食物之间的区别，以及与大量等价物作进一步测试的决定，都与经济合作发展组织所定义的相似（1996） 。 联合国粮食与农业组织/世界卫生组织的食品法典委员会致力于国际食物标准的融洽。通过食品法典委员会制定的食品标准应当被各国政府采纳。生物技术食品法典特设政府有任务发展转基因食品的标准，指导方针和其他建议。2000 年 3 月，在千叶（日本）的第一届会议上，关于转基因食品的“风险评估”和“风险分析”定义被同意。风险评估包括诸如食品安全，大量的等效性和长期的健康影响，而风险分析可能包括决策和上市后监测等问题。 自从 1996 年的磋商会后，2000 年五月/六月在瑞士日内瓦举行专家磋商会来聚集评价
6、经验。审议的议题包括实质等同性，基因改造，食品安全，营养的影响，抗生素抗性标记基因和过敏源。对转基因食品的安全性评估，研讨会赞同等价物作为一个有效的方法，并得出结论，目前没有合适可利用的替代策略。概念的应用是一个安全评估的起点，而不是一个终点。鉴别转基因食物与它合适的对应物之间的相似和可能不同，这应该作进一步的评估 对由于基因改造过程中而发生的潜在不确定效应的问题，进行了检查，如现有性状的缺失或增加一个新的性状。这种不确定效应并不只是针对 DNA 复制技术，在传统育种方面也经常发生。检测这种效应的现有方法集中于对已知营养物和毒物的化学分析（定向方法） 。为了提高检测这种不确定效果的可能性，分析
7、/辨别方法被认为是有用的方案（非定向办法） 。当在不确定效果的发生率增加时，基因的大量修改对于植物非常有利（第二代转基因食品） 。 动物研究认为有必要获取新表达蛋白质的特征，类似于传统的食品添加剂的毒性试验。整个食品的测试可能会考虑，除了期望的以外，合成物的相关变化也可能发生；然而，这些研究应该在个例的基础上被考虑，把这种研究的局限性考虑进去。证明长期消费食品安全的最低要求是对慢性毒性 90 天的研究。如果一个 90 天的研究结果表明出现诸如组织增生的不良反应，可能还需要更长期的研究。专家磋商会指出，在一般情况下，所有食物的长期潜在影响很少被知道，并且鉴别这种效果可能非常困难，是由于许多混杂因
8、素和巨大的遗传变异存在与食物有关的效果。因此，鉴别长期的影响，特别是由于转基因食品引起的影响是极不可能的。流行病学研究不容易识别这种在高背景下传统食品的不良影响。研讨会认为，市场前的安全评估已经给出了一个保证，转基因食品和其对3应传统等价3物一样安全。如随机控制人体特征的试验研究，如果正确执行，为人类的安全，可能在中长期提供更多的证据。 从上面，我们可以清楚地看到，因为转基因食品并不是完全安全的，但我们的国家和一些国际组织如联合国粮农组织和世界卫生组织制定了足够数量的规章制度，以减少风险，更何况，现在没有任何严重的转基因安全事故发生。我们可以没有那么多顾虑来享受转基因技术的好处。 ，我们也尝试
9、了一些能避免事故的新方式。只要我们遵循规则和我们可以利用的现代生物技术，转基因食品是足够安全。1英文文献Safety problems of genetically modified foodAt an early stage in the introduction of recombinant-DNA technology in modern plant breeding and biotechnological food production systems, efforts began to define intern-ationally harmonized evaluation st
10、rategies for the safety of foods derived from genetic-ally modified organisms (GMOs). Two years after the first successful transformation e-xperiment in plants (tobacco) in 1988, the International Food Biotechnology Council (IFBC) published the first report on the issue of safety assessment of these
11、 new varieties (IFBC, 1990). The comparative approach described in this report has laid the basis f-or later safety evaluation strategies. Other organizations, such as the Organisation for Economic Cooperation and Development (OECD), the Food and Agriculture Organization of the United Nations (FAO)
12、and the World Health Organization (WHO) and the International Life Sciences Institute (ILSI) have developed further guidelines for safety assessment which have obtained broad international consensus among experts on food safety evaluation. At 1993, the OECD formulated the concept of substantial equi
13、valence as a guiding tool for the assessment of genetically modified foods, which has been further elabo-rated in the follwing years.The concept of substantial equivalence is part of a safety evaluation framework based on the idea that e-xisting foods can serve as a basis for co-mparing the properti
14、es of a genetically modifi-ed food with the appropriate counterpa-rt. The existing food supply is considered to b-e safe, as experienced by a long histoy of use, although it is recognized that foods ma-y contain many anti-nutrients and toxi-cants which, at certain levels of consumption, ma-y induce
15、deleterious effects in hum-ans and animals. Application of the concept is not a safety assessment per se, but hel-ps to identify similarities and potential differenc-es between the existing food and the new product, which is then subject to further tox-icological investigation. Three scena-rios are
16、envisioned in which the genetically mod-ified plant or food would be (i) subs-2tantially equivalent; (ii) substantially equivalent e-xcept for the inserted trait; or (iii) not equivalent at all. A compositional analysis of k-ey components, including key nutrients and natural toxicants, is the basis
17、of assessment of substantial equivalence, in ad-dition to phenotypic and agronomic characteristics of the genetically modified plant. In the first scenario, no further specific testing is required as the product has beenchar-acterized as substantially equivalent to a traditional counterpart whose co
18、nsumption i-s considered to be safe, for example, starch from potato. In the second scenario, substantial equivalence would apply except for the inserted trait, and so the focus of t-he safety testing is on this trait, for example, an insecticidal protein of genetically mod-ified tomato. Safety test
19、s include specific toxicity testing according to the nature and func-tion of the newly expressed protein; potential occurence of unintended effects; p-otential for gene transfer from genetically modified foods to human/animal gut flora; t-he potential allergenicity of the newly inserted traits; and
20、the role of the new food in t-he diet . In the third scenario, the novel crop or food would be not substantially equiv-alent with a traditional counterpart, and a case-by-case assessment of the new food m-ust be carried out according to the characteristics of the new product. FAO (short for Food and
21、 Agriculture Organization ) and WHO (World Healt Organization)been organizing workshops and consultations on the safety of G-MOs since 1990. At the Joint FAO/WHO Consultation in 1996 (FAO/WHO, 1996) ,itwas recommended that the safety evaluation should be based on the concept of substa-ntial equivale
22、nce, which is a dynamic, analytical exercise in the assessment of the saf-ety of a new food relative to an existing food. The following parameters should be co-nsidered to determine the substantial equivalence of a genetically modified plant: mo-lecular characterization; phenotypic characteristics;
23、key nutrients; toxicants; and aller-gens.The distinction between three levels of substantial equivalence (complete, partial, non-) of the novel food to its counterpart, and the subsequent decisions for further tes-ting based upon substantial equivalence, are similar to those defined by OECD (1996) 3
24、The Codex Alimentarius Commission of FAO/WHO is committed to the internationalharmonization of food standards. Food standards developed by Codex Alimentarius s-hould be adopted by the participating national governments. The Codex ad hoc Interg-overn mental Task Force on Foods Derived from Biotechnol
25、ogy has the task to devel-op standards, guidelines and other recommendations for genetically modified foods. During its first session in Chiba (Japan) in March 2000 definitions were agreed concer-ning the risk assessment and risk analysis of genetically modified foods. Risk asse-ssment covers issues
26、 such as food safety, substantial equivalence and long-term healt-h effects, while risk analysis may include decision-making and post-market monitori-ng. An Expert Consultation held in Geneva, Switzerland in May/June 2000 evaluate-d experiences gathered since the 1996 Consultation. Topics considered
27、 included subst-antial equivalence, unintended effects of genetic modification, food safety, nutritional effects, antibiotic resistance marker genes, and allergenicity. The Consultation endors-ed the concept of substantial equivalence as a pragmatic approach for the safety asses-sment of genetically
28、 modified foods, and concluded that at present no suitable alterna-tive strategies are available. Application of the concept is a starting point for safety a-ssessment, rather than an end-point. It identifies similarities and possible differences b-etween the genetically modified food and its approp
29、riate counterpart, which should th-en be assessed further. The issue of the potential occurrence of unintended effects due to the genetic modification process, such as the loss of existing traits or the acquisition of new ones, was examined. The occurrence of unintended effects is not unique for the
30、 application of recDNA techniques, but also occurs frequently in conventional breeding. Present a-pproaches to detecting such effects focus on chemical analysis of known nutrients andtoxicants (targeted approach). In order to increase the possibility of detecting uninten-ded effects, profiling/finge
31、rprinting methods are considered useful alternatives (non-targeted approach). This is of particular interest for plants with extensive modifications of the genome (second generation of genetically modified foods) where chances of th-e occurrence of unintended effects may increase. Animal studies are
32、 deemed necessary to obtain information on the characteristics4of newly expressed proteins, analogous to the conventional toxicity testing of food ad-itives. Testing of whole foods may be considered if relevant changes in composition may have taken place in addition to the expected ones; however, su
33、ch studies should b-e considered on a case-by-case basis, taking the limitations of this type of study into account. The minimum requirement to demonstrate the safety of long-term consumpti-on of a food is a sub chronic 90-day study. Longer-term studies may be needed if the results of a 90-day study
34、 indicate adverse effects such as proliferative changes in tissu-es. The Expert Consultation noted that, in general, very little is known about the pot-ential long-term effects of any foods, and that identification of such effects may be ver-y difficult, if not impossible, due to the many confoundin
35、g factors and the great genet-ic variability in food-related effects among the population. Thus the identification of long-term effects specifically attributable to genetically modified foods is highly unlik-ely. Epidemiological studies are not likely to identify such effects given the high bac-kgro
36、und of undesirable effects of conventional foods. The Consultation was of the opi-nion that pre-market safety assessment already gives an assurance that genetically m-odified foods are as safe as their conventional counterparts. Experimental studies, suc-h as randomized controlled human trials, if p
37、roperly performed, might provide additio-nal evidence for human safety in the medium to long term. From the above,we can clearly see that since the GM food isnt exactly safe,but o-ur country and some international organizations like FAO and WHO developed a suff-icient number of rules and regulations
38、 to reduce the risk of accidents.and whats more,since now not any serious GM safety accident has happened.so we can enjoy the bene-fits of the modern biotechnology.so much worries isnt needed,and we are also trying some new way which can avoid the accident.GM food is safe enough only if we follo-w the rules.and we can use the modern biotechnology.
